1. Field of the Invention
The invention relates to an electrical edge connector for a substrate, and particularly to means for clamping together a substrate inserted into an edge connector.
2. Description of Related Art
Edge connectors for the external connection of conductors on, for example, printed circuit boards or on glass substrates of liquid crystal or LED (light emitting diode) display panels are widely used in electronic apparatus.
In many forms of construction, the holding power of an edge connector of this kind on the substrate is dependent solely on the number of contact members of the edge connector and their contact pressure on the substrate. The thickness of the substrate, the coefficient of friction between on the one hand a contact surface of the contact member and, on the other hand, a conductor of the substrate, and the coefficient of friction between a surface of the substrate and a pressure surface of the contact member, for example a spring arm, are usually important factors in this respect.
In many cases, high contact pressure will not be possible because the force required to push the connector over the edge of the substrate would then be too great. If the force required for this purpose is too great, the conductors on the substrate, which in many cases are in the form of thin strips, can in fact easily be damaged. The edges of glass substrates, for example, of liquid crystal display panels, are in addition very vulnerable, so that these edges can easily be damaged if too much force is used for their connection.
On the other hand, a powerful force is required for holding the edge connector on the substrate in applications where the substrate is subject to jolts, shocks or the like. This may for example be the case when the assembly is used in aircraft, ships or motor vehicles.
Because of these conflicting requirements for high contact pressure for holding power on the one hand, and smaller forces for making the electrical connection, on the other hand, it may be necessary to use an additional clamping means to eliminate accidental detachment of the edge connector from the substrate.